As a device for distributing various kinds of liquid materials in units of a predetermined amount, there is known a device, called a “dispenser”, including a container storing a liquid material, and discharging the liquid material in units of a predetermined amount from a nozzle, which is connected to the container, by the action of gas pressure or mechanical pressure. As one example of dispensers proposed by the applicant, Patent Document 1 discloses a dispenser in which the liquid material to be discharged is filled into a metering hole by moving a plunger backward, the plunger being held in slide contact with an inner wall of the metering hole, and the liquid material is discharged from the nozzle by moving the plunger forward.
In trying to utilize the dispenser to discharge, particular one among various kinds of liquid materials, especially a liquid mixed with solid particles having greater specific weight than the liquid, a problem arises, for example, in that the solid particles gradually precipitate onto a bottom portion of the container or into a recess in the flow path with the lapse of time. Moreover, if dispersion of the solid particles is insufficient, the nozzle is clogged, thus causing such a trouble that the liquid material can no longer be discharged. To prevent the above trouble, the solid particles need to be stirred and held in a state dispersed in the liquid.
Recently, the dispenser of the type having the structure disclosed in Patent Document 1 has been utilized in many cases to discharge the liquid mixed with the solid particles (e.g., a light transmissive resin mixed with LED phosphors). However, because the dispenser disclosed in Patent Document 1 does not include any means for stirring the liquid, the means for stirring the liquid is required.
A liquid is generally stirred by a stirrer provided on the container. Even with the provision of the stirrer on the container, however, the liquid material cannot be often discharged in the state of the solid particles being dispersed in the liquid material because precipitation of the solid particles occurs midway a pipe connecting the container and a discharge mechanism to each other. Aiming to solve the above problem, a method and a device, described below, have been proposed until now.
Patent Document 2 discloses a liquid discharge method including an adjustment step of applying pressure of 0.001 MPa to 10 MPa to a liquid containing solid particles, the liquid filled in at least one of two or more containers, reducing pressure of a liquid in at least one remaining container to be lower than the pressure of the liquid in the aforementioned at least one container, and adjusting a flow rate of the liquid in a flow path between the two or more containers by flow-rate adjustment means while allowing the liquid to flow through the flow path, and a discharge step of discharging the liquid from the flow path through a valve.
Patent Document 3 discloses a discharge device for a filler-mixed liquid material in which a discharge path having a substantially uniform inner diameter and extending up to a discharge port is disposed at a lower end of a container storing the filler-mixed liquid material, a valve having a penetration path and including a rotary valve body is disposed at a position near the discharge port, and a reciprocating pump is connected to the discharge path on the upstream side of the valve.